mongodb/db/query.cpp

// query.cpp

#include "stdafx.h"
#include "query.h"
#include "pdfile.h"
#include "jsobj.h"
#include "../util/builder.h"
#include <time.h>

int nextCursorId = 1;

void deleteObjects(const char *ns, JSObj pattern, bool justOne) {
	cout << "delete ns:" << ns << " queryobjsize:" << 
		pattern.objsize() << endl;

	if( strncmp(ns, "system.", 7) == 0 ) { 
		cout << "ERROR: attempt to delete in system namespace " << ns << endl;
		return;
	}

	JSMatcher matcher(pattern);

	auto_ptr<Cursor> c = theDataFileMgr.findAll(ns);
	while( c->ok() ) {
		Record *r = c->_current();
		DiskLoc rloc = c->currLoc();
		c->advance(); // must advance before deleting as the next ptr will die
		JSObj js(r);
		if( matcher.matches(js) ) {
			cout << "  found match to delete" << endl;
			theDataFileMgr.deleteRecord(ns, r, rloc);
			if( justOne )
				return;
		}
	}
}

void updateObjects(const char *ns, JSObj updateobj, JSObj pattern, bool upsert) {
	cout << "update ns:" << ns << " objsize:" << updateobj.objsize() << " queryobjsize:" << 
		pattern.objsize() << endl;

	if( strncmp(ns, "system.", 7) == 0 ) { 
		cout << "ERROR: attempt to update in system namespace " << ns << endl;
		return;
	}

	JSMatcher matcher(pattern);

	auto_ptr<Cursor> c = theDataFileMgr.findAll(ns);
	while( c->ok() ) {
		Record *r = c->_current();
		JSObj js(r);
		if( matcher.matches(js) ) {
			cout << "  found match to update" << endl;
			theDataFileMgr.update(ns, r, c->currLoc(), updateobj.objdata(), updateobj.objsize());
			return;
		}
		c->advance();
	}

	cout << "  no match found. ";
	if( upsert )
		cout << "doing upsert.";
	cout << endl;
	if( upsert )
		theDataFileMgr.insert(ns, (void*) updateobj.objdata(), updateobj.objsize());
}

typedef map<long long, ClientCursor*> CCMap;
CCMap clientCursors;

long long allocCursorId() { 
	long long x;
	while( 1 ) {
		x = (((long long)rand()) << 32);
		x = x | time(0);
		if( clientCursors.count(x) == 0 )
			break;
	}
	return x;
}

QueryResult* runQuery(const char *ns, int ntoreturn, JSObj jsobj) {

	cout << "runQuery ns:" << ns << " ntoreturn:" << ntoreturn << " queryobjsize:" << 
		jsobj.objsize() << endl;

	BufBuilder b;

	auto_ptr<JSMatcher> matcher(new JSMatcher(jsobj));

	QueryResult *qr = 0;
	b.skip(sizeof(QueryResult));

	int n = 0;

	auto_ptr<Cursor> c = 
		//		strcmp(ns, "system.namespaces") == 0 ? 
		//		makeNamespaceCursor() : 
	    theDataFileMgr.findAll(ns);

	long long cursorid = 0;
	while( c->ok() ) {
		JSObj js = c->current();
		if( matcher->matches(js) ) {
			b.append((void*) js.objdata(), js.objsize());
			n++;
			if( n >= ntoreturn && ntoreturn != 0 ) {
				// more...so save a cursor
				ClientCursor *cc = new ClientCursor();
				cc->c = c;
				cursorid = allocCursorId();
				cc->cursorid = cursorid;
				cc->matcher = matcher;
				cc->ns = ns;
				cc->pos = n;
				clientCursors[cursorid] = cc;
				break;
			}
		}
		c->advance();
	}

	qr = (QueryResult *) b.buf();
	qr->len = b.len();
	qr->reserved = 0;
	qr->operation = opReply;
	qr->cursorId = cursorid;
	qr->startingFrom = 0;
	qr->nReturned = n;
	b.decouple();

	return qr;
}

QueryResult* getMore(const char *ns, int ntoreturn, long long cursorid) {

	cout << "getMore ns:" << ns << " ntoreturn:" << ntoreturn << " cursorid:" << 
		cursorid << endl;

	BufBuilder b;

	ClientCursor *cc = 0;
	CCMap::iterator it = clientCursors.find(cursorid);
	if( it == clientCursors.end() ) { 
		cout << "Cursor not found in map.  cursorid: " << cursorid << endl;
	}
	else {
		cc = it->second;
	}

	b.skip(sizeof(QueryResult));

	int start = 0;
	int n = 0;

	if( cc ) {
		start = cc->pos;
		Cursor *c = cc->c.get();
		while( 1 ) {
			if( !c->ok() ) {
				// done!  kill cursor.
				cursorid = 0;
				clientCursors.erase(it);
				delete cc;
				cc = 0;
				break;
			}
			JSObj js = c->current();
			if( cc->matcher->matches(js) ) {
				b.append((void*) js.objdata(), js.objsize());
				n++;
				if( n >= ntoreturn && ntoreturn != 0 ) {
					cc->pos += n;
					break;
				}
			}
		}
		c->advance();
	}

	QueryResult *qr = (QueryResult *) b.buf();
	qr->cursorId = cursorid;
	qr->startingFrom = start;
	qr->len = b.len();
	qr->reserved = 0;
	qr->operation = opReply;
	qr->nReturned = n;
	b.decouple();

	return qr;
}